This invention relates to sheaths for the remote steering, guidance, navigation and manipulation of flexible instruments, such as endoscopes.
Endoscopic procedures typically employ endoscopic instruments that are maneuvered within or towards a target organ or tissue from a position outside the body. Examples of endoscopic procedures include sigmoidoscopy, colonoscopy, esophagogastroduodenoscopy, and bronchoscopy. Typically flexible endoscopes, which have flexible insertion tubes, are used for such procedures. The insertion tube of the endoscope is advanced by pushing it forward, and retracted by pulling it back. The tip of the tube may be directed by twisting and general up/down and left/right movements. Oftentimes, this limited range of motion makes it difficult to negotiate acute angles, creating patient discomfort and increasing the risk of trauma to surrounding tissues.
Endoscopes can also be employed in laparoscopic procedures. Such procedures typically involve introducing a trocar into a person's body and then inserting an endoscope tube through the trocar to the desired location. Rigid endoscopes, i.e., endoscopes having a less flexible, more rigid insertion tube (also sometimes referred to as laparascopes) are more typically used in laparoscopic procedures, as the need to advance such endoscopes through constricted anatomical structures is less pronounced. Maneuverability of the endoscope deployed in this fashion is limited, with little ability to navigate the endoscope independent of moving the insertion trocar.
There have been many attempts to design endoscopes as well as catheters, with improved steerability, however, the range of motion is generally limited. For example, U.S. Pat. No. 3,557,780 to Sato; U.S. Pat. No. 5,271,381 to Ailinger et al.; U.S. Pat. No. 5,916,146 to Alotta et al.; and U.S. Pat. No. 6,270,453 to Sakai describe endoscopic instruments with one or more flexible portions that may be bent by actuation of a single set of wires. The wires are actuated from the proximal end of the instrument by rotating pinions (Sato), manipulating knobs (Ailinger et al.), a steerable arm (Alotta et al.), or by a pulley mechanism (Sato). U.S. Pat. No. 5,916,147 to Boury et al. discloses a steerable catheter having four wires that run within the catheter wall. Each wire terminates at a different part of the catheter. The proximal end of the wires extend loosely from the catheter so that the physician may pull them. The physician is able to shape and thereby steer the catheter by selectively placing the wires under tension.
Steerable endoscopes have improved range of motion as compared to non-steerable flexible endoscopes or rigid endoscopes, but their range of motion is still generally limited. Further, these devices can be laborious to use, pulling each wires separately as in Boury et al., and may require a significant amount of training to become proficient in maneuvering the device through the patient's anatomy, as in the case of knob and pulley mechanisms. In addition, steerable endoscopes are expensive to maintain. Consequently, it would be advantageous to provide an easier to use, more cost-effective system to improve steering, navigation, guidance and manipulation of conventional flexible endoscopes.